Advances in optical methodology for studies of dynamic characteristics of MEMS microengines rotating at high speeds

摘要

Development of MEMS microengines capable of rotating at 1,000,000rpm constitutes one of the most challenging tasks in today's micromechanics and requires advancements in dynamic test methodologies to enable refinement and optimization of designs. We have developed an optoelectronic laser interferometry microscope (OELIM) methodology for rapid characterization of motion dynamics of MEMS. In this study, electrostatic comb drive actuated microengines comprised of a 64 pm diameter drivegear and a 300μm outputgear (loadgear) were characterized dynamically. The actuators were driven by synchronized input signals generated by an arbitrary waveform generator. Out-of-plane wobble on rotating microengines was measured as a function of the input signals. Typically, the out-of-plane motions ranged from zero to ±462 nm and from zero to ±514 nm for the drive and output gears, respectively. These motions are due to kinematics and kinetics caused by impulsive loading forces generated by input signals. The wobble was also observed to depend on the angular position in the rotation cycle. This can be related to the forces exerted on the drivegear by the pin during the cycle.